ECG Flashcards by Riyanna Day

Which of the following leads are considered bipolar limb leads in a standard 12-lead ECG?

A) aVR, aVL, aVF
B) I, II, III
C) V1, V2, V3
D) V3R, V4R

B) I, II, III

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What is the main purpose of the Wilson central terminal in ECG lead placement?

A) To enhance the electrical activity from the limbs
B) To create a constant negative pole for unipolar leads
C) To provide a backup in case of lead failure
D) To record heart rate

B) To create a constant negative pole for unipolar leads

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How does the positioning of the patient (sitting vs. supine) affect the ECG?

A) It does not affect the ECG.
B) It changes the lead’s electrical properties.
C) It alters the relationship of chest leads to the heart.
D) It only affects limb leads.

C) It alters the relationship of chest leads to the heart.

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What can happen if a chest lead is placed in an interspace that is too high or too low?

A) The ECG will be unaffected.
B) The ECG waveform recorded will change.
C) It will cause a permanent heart condition.
D) It will only affect limb leads.

B) The ECG waveform recorded will change.

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In which situations are right-sided chest leads (V3R and V4R) typically used?

A) Only in pediatric patients
B) To assess limb lead quality
C) To diagnose right ventricular infarction
D) In routine physical examinations

C) To diagnose right ventricular infarction

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Why is consistency in lead placement important when recording serial ECGs?

A) To minimize patient discomfort
B) To ensure accurate heart rate measurement
C) To avoid significant changes in ECG patterns
D) To improve the speed of recording

C) To avoid significant changes in ECG patterns

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What does the P wave in an ECG represent?

A) Ventricular repolarization
B) Atrial depolarization
C) Atrial repolarization
D) Ventricular depolarization

B) Atrial depolarization

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Which component of the ECG reflects ventricular depolarization?

A) P wave
B) PR interval
C) QRS complex
D) T wave

C) QRS complex

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What is the significance of the ST segment and T wave in the ECG waveform?

A) They indicate atrial contraction.
B) They reflect ventricular repolarization.
C) They show electrical activity of the AV node.
D) They are silent events with no clinical relevance.

B) They reflect ventricular repolarization.

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What does the U wave represent in an ECG?

A) Atrial contraction
B) Ventricular depolarization
C) An electromechanical event related to ventricular relaxation
D) The electrical activity of the AV node

C) An electromechanical event related to ventricular relaxation

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Why is the depolarization of the sinus node not recorded in an ECG?

A) It occurs after the P wave.
B) Its voltage signal is too small to be detected.
C) It is not relevant to cardiac function.
D) It occurs during the QRS complex.

B) Its voltage signal is too small to be detected.

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What occurs during the PR interval that is electrocardiographically silent?

A) Atrial depolarization
B) Ventricular repolarization
C) Electrical activity of the AV node and His-Purkinje system
D) Sinus node depolarization

C) Electrical activity of the AV node and His-Purkinje system

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What primarily causes the P wave in an ECG?

A) Depolarization of the ventricles
B) Voltage gradients during atrial depolarization
C) Repolarization of the atria
D) Electrical activity of the AV node

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How is the shape and duration of the P wave determined?

A) By the position of the ECG electrodes
B) By the sequence and timing of atrial depolarization
C) By the overall heart rate
D) By the strength of the heart muscle

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In which leads is the P wave typically upright or positive?

A) I, II, aVR
B) aVL, V3 to V6
C) III, aVF
D) Both A and B

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What happens to the P wave configuration if the ectopic atrial focus is located far from the sinus node?

A) It remains unchanged.
B) It resembles the normal sinus P wave.
C) It becomes more abnormal in shape.
D) It disappears entirely.

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If an impulse arises from the inferior portion of the atrium, how will the P waves appear in leads II, III, and aVF?

A) Upright
B) Biphasic
C) Inverted
D) Flattened

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What effect can atrial hypertrophy and/or dilation have on the P wave?

A) It can cause the P wave to disappear.
B) It can affect the amplitude and duration of the P wave.
C) It has no effect on the P wave.
D) It causes the P wave to become biphasic in all leads.

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What does the PR interval encompass in an ECG?

A) Only the P wave
B) The P wave and the QRS complex
C) The P wave and the PR segment
D) The QRS complex and the T wave

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What components make up the PR segment?

A) Atrial repolarization and depolarization of the AV junction
B) Ventricular repolarization and depolarization
C) Sinus node activity and atrial contraction
D) Atrial depolarization and ventricular contraction

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Which of the following factors can lead to prolonged AV conduction and an increased PR interval?

A) Decreased vagal tone
B) Increased sympathetic tone
C) Digitalis and β-adrenergic blocking agents
D) High potassium levels

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What occurs in cases of complete AV block regarding the P waves and QRS complexes?

A) They become identical.
B) The P waves are dissociated from the QRS complexes.
C) The QRS complexes disappear.
D) The P waves merge with the QRS complexes.

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How does the PR interval change in the presence of an AV nodal bypass tract, such as in the Wolff-Parkinson-White pattern?

A) It is prolonged.
B) It becomes absent.
C) It is shortened.
D) It remains unchanged.

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Which of the following can lead to a shortened PR interval?

A) Increased vagal tone
B) AV nodal bypass tract
C) Ischemia
D) Inflammatory diseases

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What does the QRS complex primarily reflect in an ECG? A) Atrial depolarization B) Ventricular depolarization C) Atrial repolarization D) Ventricular repolarization

Which part of the ventricle is the first to be depolarized? A) Right ventricle B) Left ventricle C) Interventricular septum D) Apex of the heart

In which leads is the QRS complex typically upright or positive due to left ventricular dominance? A) I, V5, V6 B) aVR, V1 C) II, III, aVF D) I, II, III

What abnormality can lead to the identification of right ventricular depolarization on the ECG? A) Left bundle branch block B) Right bundle branch block C) Normal sinus rhythm D) Ventricular ectopic beats

How does the QRS complex change in shape and duration with bundle branch blocks? A) It remains unchanged. B) It is prolonged and may show significant changes in configuration. C) It becomes biphasic. D) It is always inverted.

What can cause intraventricular conduction abnormalities without a change in QRS configuration? A) Bundle branch blocks B) Fascicular blocks C) Cardioactive drugs and increased extracellular potassium D) Ventricular ectopic beats

What do fascicular blocks reflect in the conduction system? A) Conduction slowing in the right bundle branch B) Conduction slowing in one fascicle of the left bundle C) Complete blockage of the AV node D) Normal conduction through the ventricles

How do fascicular blocks affect the QRS complex? A) They have no effect on the QRS complex. B) They alter the initial portion of the QRS complex and the electrical axis. C) They only increase the duration of the QRS complex. D) They solely indicate the presence of a previous myocardial infarction.

What is true about right bundle branch block (RBBB)? A) It affects the initial portion of the QRS complex. B) It obscures the diagnosis of previous myocardial infarction. C) It allows for appreciation of previous MI changes in the ECG. D) It mimics left ventricular hypertrophy changes.

How does left bundle branch block (LBBB) influence the QRS complex? A) It has no effect on the QRS complex. B) It affects the initial portion, obscuring changes from previous MI or hypertrophy. C) It only increases the QRS duration without affecting shape. D) It allows for clear identification of right ventricular hypertrophy.

What is a characteristic feature of intraventricular conduction abnormalities? A) They only affect the QRS complex. B) They are always associated with changes in ST segment and T wave. C) They have no effect on repolarization. D) They only occur in patients with myocardial infarction.

What does "rate-dependent aberrant ventricular conduction" refer to? A) Conduction disturbances that occur regardless of heart rate. B) Changes in conduction that appear only at certain heart rates or after premature beats. C) A permanent conduction defect. D) An abnormal rhythm caused by ectopic beats.

What factors can influence the amplitude of the QRS complex? A) Age, sex, race, and body mass B) Only age and sex C) Heart rate and rhythm D) Medication use exclusively

In left ventricular hypertrophy, which leads typically show increased amplitude of the QRS complex? A) V1 and V2 B) I and II C) V5 and V6 D) aVR and aVL

What is a challenge in diagnosing right ventricular hypertrophy electrocardiographically? A) It always shows increased R-wave amplitude. B) It initially causes cancellation of left ventricular forces. C) It is associated with significant changes in QRS duration. D) It causes a pronounced increase in S-wave amplitude.

What do the ST segment and T wave primarily reflect in an ECG? A) Atrial depolarization B) Ventricular repolarization C) Atrial repolarization D) Ventricular depolarization

Why is the ST segment isoelectric? A) There are no voltage gradients present during this phase. B) The heart is in diastole during the ST segment. C) It only reflects atrial activity. D) It occurs during ventricular contraction.

What causes the T wave in an ECG? A) Atrial depolarization B) Rapid and sequential repolarization of ventricular cells C) Conduction through the AV node D) Isovolumetric contraction

upright? A) aVR and V1 B) I, V5, and V6 C) II and III D) V1 and V2

What does ST segment elevation indicate? A) Normal ventricular repolarization B) Presence of voltage gradients during plateau or resting phases of action potentials C) Abnormalities in atrial conduction D) Decreased heart rate

Which condition is NOT commonly associated with ST segment depression? A) Left ventricular hypertrophy B) Low serum potassium C) Acute transmural ischemia D) Cardioactive drugs

What guideline is true regarding T-wave amplitude? A) It should always be less than 10% of the QRS amplitude. B) It should be ≥10% of the QRS amplitude. C) It is irrelevant in ECG interpretation. D) It is only relevant in leads V5 and V6.

Inverted T waves in lead I are: A) Normal findings in healthy individuals. B) Always abnormal and suggestive of underlying cardiac pathology. C) Common in young males. D) Nonspecific and often benign.

Where is the U wave most easily observed on an ECG? A) Leads I and II B) Leads V2 to V4 C) Leads V5 and V6 D) Leads aVR and aVL

What is the typical amplitude of the U wave in relation to the T wave? A) Equal to the T wave B) Less than one-third of the T wave C) Greater than the T wave D) Approximately half of the T wave

An increase in U-wave amplitude is frequently associated with which of the following conditions? A) Hyperkalemia B) Hypokalemia C) Atrial fibrillation D) Myocardial infarction

What can cause notching of the T wave that may resemble an increased U wave? A) Ischemia B) Congenital long QT syndrome C) Ventricular hypertrophy D) Bundle branch block

The U wave may arise within which portion of the T wave? A) The initial portion B) The terminal portion C) The middle portion D) It does not arise within the T wave

What does the QT interval measure? A) From the onset of the Q wave to the end of the P wave B) From the onset of the Q wave to the end of the T wave C) From the onset of the R wave to the end of the S wave D) From the end of the P wave to the end of the T wave

Which factor can cause the QT interval to lengthen? A) Increased heart rate B) Low serum potassium C) Increased body temperature D) High serum calcium

What is a significant clinical risk associated with lengthening of the QT interval? A) Atrial flutter B) Torsades de pointes C) Sinus bradycardia D) Atrioventricular block

Which electrolyte abnormality is NOT associated with prolongation of the QT interval? A) Low serum potassium B) Low serum calcium C) High serum sodium D) High serum potassium

What ECG changes are associated with low potassium? A) Prominent U wave and T-wave inversion B) ST-segment elevation and short QT interval C) ST-segment depression, T-wave changes, and prominent U wave D) Normal ST segment and tall T waves

What is the typical effect of high serum potassium on the T wave? A) It lengthens the T wave. B) It shortens the duration of the T wave and makes it more symmetrical. C) It causes T wave inversion. D) It has no effect on the T wave.

In which scenario is marked QT prolongation and deeply inverted T waves commonly observed? A) During exercise testing B) In the first several days after an acute myocardial infarction C) In patients with chronic hypertension D) In healthy individuals

What ECG changes can occur after a cerebrovascular accident? A) Prominent U waves B) T-wave inversion and QT interval lengthening C) Shortened QT interval D) Elevated ST segment

What is the earliest ECG manifestation of acute transmural ischemia? A) ST-segment elevation B) Abnormal Q waves C) T-wave peaking D) T-wave inversion

Which of the following changes is most frequently observed within minutes of the onset of acute myocardial ischemia? A) Abnormal Q waves B) T-wave inversion C) ST-segment elevation and/or depression D) Peaking of the T wave

What causes the ST segment changes seen in acute myocardial ischemia? A) Decreased heart rate B) Voltage gradients across the ischemic border C) Increased myocardial oxygen supply D) Changes in the QRS complex

In the case of subendocardial ischemia, what type of ST segment change is typically recorded? A) ST segment elevation B) ST segment depression C) No change in the ST segment D) Peaking of the T wave

What do abnormal Q waves indicate in the context of myocardial infarction? A) Transient ischemia B) Normal cardiac function C) Absent conduction through the infarcted region D) Increased cardiac output

Which leads would most likely record ST elevation in the event of transmural ischemia? A) Leads that do not overlie the ischemic region B) Leads directly overlying the ischemic region C) All limb leads D) Any lead in the chest

Abnormal Q waves that mimic those associated with infarction may also occur in which of the following conditions? A) Left ventricular hypertrophy B) Coronary artery spasm C) Acute coronary syndrome D) Pericarditis

The sequence of ECG changes associated with acute ischemia includes which of the following? A) T-wave inversion, abnormal Q waves, ST elevation B) ST elevation, peaking of T waves, abnormal Q waves C) Peaking of T waves, ST elevation/depression, abnormal Q waves, T-wave inversion D) Abnormal Q waves, T-wave inversion, ST segment depression

What heart rate is considered tachycardia? A) <60 beats/min B) 60-100 beats/min C) >100 beats/min D) 40-60 beats/min

Which arrhythmia is characterized by rapid and regular atrial contractions? A) Atrial fibrillation B) Atrial flutter C) Ventricular tachycardia D) Sinus tachycardia

To diagnose the type of tachycardia present, which components of the ECG are analyzed? A) Only the QRS complex B) Rate, configuration of the P wave, and relationship to QRS complexes C) Only the T wave D) The ST segment only

What is the heart rate range for bradycardia? A) <60 beats/min B) 60-100 beats/min C) >100 beats/min D) 40-60 beats/min

Which of the following could cause an irregular rhythm on an ECG? A) Only sinus tachycardia B) Atrial fibrillation and premature beats C) Atrial flutter only D) Complete heart block only

What is essential for diagnosing bradycardia or heart block using the ECG? A) Analyzing only the T wave B) Noting the rate, regularity, and P wave configuration C) Only measuring the ST segment D) Checking the amplitude of the QRS complex

Atrial fibrillation is characterized by: A) Regular P waves B) Rapid atrial contractions C) Irregular ventricular response D) Normal QRS complexes

Which condition could lead to a second-degree AV block? A) Sinus tachycardia B) Atrial flutter C) Atrial fibrillation D) AV nodal reentrant tachycardia

What condition can be detected on a screening ECG? A) Only coronary artery disease B) Left ventricular hypertrophy C) Mitral valve prolapse D) Atrial fibrillation

What was the recommendation from the U.S. Preventive Services Task Force regarding routine ECGs in asymptomatic low-risk individuals? A) Recommend routine ECGs B) Advise against routine ECGs C) Recommend ECGs only for athletes D) Suggest ECGs for all adults over 40

Which of the following conditions is specifically associated with an increased risk of sudden death in athletes? A) Sinus bradycardia B) Long QT syndrome C) Atrial flutter D) Heart block

What is a concern regarding ECG screening in the general population? A) High cost of ECG machines B) Lack of trained personnel C) Variable specificity for detecting conditions D) Inability to detect heart disease

In the context of preparticipation screening for athletes, what is an area of ongoing investigation? A) Effects of diet on heart health B) The impact of age, race, sex, and training on normal ECG variants C) The role of echocardiograms D) The necessity of cardiac MRI

The Wolff-Parkinson-White pattern is associated with which finding on an ECG? A) Prolonged PR interval B) Shortened QT interval C) Delta wave D) Inverted T waves

What is the main limitation of using ECGs as a screening tool in asymptomatic patients? A) They are too expensive. B) They cannot detect arrhythmias. C) The specificity for detecting certain conditions is highly variable. D) They are not widely available.

C) The specificity for detecting certain conditions is highly variable.